Take one dose Viagra, add in a hefty serving of Benefiber, toss with a healthy lust for life, and what do you get? Hugh Hefner at 85.

A little more than a week after Crystal Harris called off their June 18 nuptials, the forever-frisky Playboy mogul has filled his vacant girlfriend position. Again.

In addition to newly minted "best girl" Anna Sophia Berglund, who's better known to Playboy readers as Miss January, he's tapped Shera Bechard, who also just happens to be a bona fide Playboy centerfold.

"Shera is both our November 2011 Playmate and my new girlfriend," Hef tweeted on Monday when asked about her current title (actually, she was the November 2010 Playmate, but hey, the dude is 85 -- let's cut him some slack.)

At 27, Bechard is a couple years older than Crystal and Anna, but the Canadian native still embodies the qualities Hugh requires in a partner: integrity, loyalty, braininess and sincerity.

Just kidding: Shera is a blonde with huge knockers.

According to her website, she's also "a pretty private" person, as you'd expect from any young lady who agrees to pose butt nekkid for Playboy and snuggle up to Hef. Her pet peeve is "people mistaking my shyness for snobbery."

Shera's turn-ons, as listed in her 2010 Playmate data sheet, include "guys who make me laugh so hard I hyperventilate" and "cowboys with a bit of facial hair."

Her biggest turnoff is "men who aren't open to exploring their sexuality with me."

Still, not everyone is on board with Hef's quick rebounds -- and he doesn't care a bit. "A new GF is the only logical response to heartbreak, Jeff," he responded to one critical follower. "How can I feel badly about dealing with what has been a truly devastating experience? I'm grateful for the support."

And he made sure to point out, "The interest in Shera came after the stunner from Crystal."

Meanwhile, Bechard's promotion to No. 2 girlfriend status has allowed Crystal to milk a little more drama from her fizzled romance.

The would-be Mrs. Hefner, who denies trying to hock her $90,000 engagement ring, shared a few of the sour grapes she's sucking on.

"I was replaced the day after I left," she tweeted on Monday afternoon. "#Expected."